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PHEVs produce almost five times greater global warming emissions than official data show, according to a recent analysis.

Widening Discrepancy In Lab and Actual CO2 Output

Statistics reveals that PHEVs release only one-fifth lower CO₂ than traditional gas and diesel vehicles, based on analysis carried out by a advocacy organization. That contrasts sharply with laboratory tests, which assumed a 75% reduction in emissions.

Analysts examined data from onboard energy use monitors of eight hundred thousand vehicles sold in the EU from 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were nearly five times higher than official figures, increased from 3.5 times in 2021.

“Real-world emissions are rising, while lab-reported emissions are decreasing,” stated a senior researcher participating in the report. “That discrepancy is growing and poses a serious issue. As a result, PHEVs emit almost as much as petrol vehicles.”

Key Reasons Behind the Discrepancy

Researchers attributed most of the difference to overestimates of the “electric driving share” – the percentage of kilometers driven in electric power relative to overall mileage. The team found that just a quarter of travel was done in electric mode, whereas lab assumptions suggested over four-fifths.

Even, when operating in electric mode, emission levels were significantly higher than official estimates. This occurred because EV motors were insufficiently powerful enough to function independently, resulting to engines burning gasoline for almost one-third of the distance completed in EV mode.

Regulatory and Financial Implications

According to estimates, the lowballing of PHEV CO2 output allowed several major carmaker groups to escape over €5bn in fines between 2021 and 2023, by falsely easing compliance with EU fleet-average CO₂ targets.

Furthermore, drivers of PHEVs could pay approximately €500 more per year in running costs than is assumed under laboratory conditions.

“The strong statements that manufacturers like to make about their plug-in hybrid vehicles are clearly far from the mark,” stated a transport expert. “Buyers are being misled into thinking that by purchasing a PHEV, they are helping the planet and cutting costs. In reality, PHEVs are little better than regular petrol and diesel vehicles in terms of energy use, CO₂ emissions, and running costs.”

Policy Discussion and Automotive Pressure

Hybrid vehicles have recently been brought back into policy debates as carmakers have lobbied the EU to relax CO₂ targets. A planned ban on sales of new internal combustion vehicles in 2035 has faced intense pressure from the car industry and opposition from EU countries with large automotive manufacturing.

Some senior officials have suggested PHEVs as a potential “compromise” option to include in the regulation.

One external energy policy expert, who was not involved with the study, called the analysis a “very useful addition” after a long period in which parts of the automotive industry claimed there was insufficient information to properly assess actual emissions.

“These findings show, beyond any doubt, that the gap in lab and real-world PHEV fuel consumption and CO₂ output is significantly greater than for gasoline or conventional vehicles,” the expert stated. “All policy adjustments regarding PHEVs should be implemented with extreme caution and in the light of that data.”